591 research outputs found
CLFE2D: A generalized plane strain finite element program laminated composites subject to mechanical and hygrothermal loading
CLFE2D is a two dimensional generalized plane strain finite element code, using a linear, four node, general quadrilateral, isoparametric element. The program is developed to calculate the displacements, strains, stresses, and strain energy densities in a finite width composite laminate. CLFE2D offers any combination of the following load types: nodal displacements, nodal forces, uniform normal strain, or hygrothermal. The program allows the user to input one set of three dimensional orthotropic material properties. The user can then specify the angle of material principal orientation for each element in the mesh. Output includes displacements, stresses, strains and strain densities at points selected by the user. An option is also available to plot the underformed and deformed finite element meshes
Displacement effect in strong-field atomic ionization by an XUV pulse
We study strong-field atomic ionization driven by an XUV pulse with a
non\-zero displacement, the quantity defined as the integral of the pulse
vector potential taken over the pulse duration. We demonstrate that the use of
such pulses may lead to an extreme sensitivity of the ionization process to
subtle changes of the parameters of a driving XUV pulse, in particular, the
ramp-on/off profile and the carrier envelope phase. We illustrate this
sensitivity for atomic hydrogen and lithium driven by few-femto\-second XUV
pulses with intensity in the range. We argue that the
observed effect is general and should modify strong-field ionization of any
atom, provided the ionization rate is sufficiently high.Comment: 5 pages, 7 figure
Fibre-optic delivery of time and frequency to VLBI station
The quality of Very Long Baseline Interferometry (VLBI) radio observations
predominantly relies on precise and ultra-stable time and frequency (T&F)
standards, usually hydrogen masers (HM), maintained locally at each VLBI
station. Here, we present an operational solution in which the VLBI
observations are routinely carried out without use of a local HM, but using
remote synchronization via a stabilized, long-distance fibre-optic link. The
T&F reference signals, traceable to international atomic timescale (TAI), are
delivered to the VLBI station from a dedicated timekeeping laboratory.
Moreover, we describe a proof-of-concept experiment where the VLBI station is
synchronized to a remote strontium optical lattice clock during the
observation.Comment: 8 pages, 8 figures, matches the version published in A&A, section
Astronomical instrumentatio
Comparing responsiveness of the EQ-5D-5L, EQ-5D-3L and EQ VAS in stroke patients
Aims: To date, evidence to support the construct validity of the EQ-5D-5L has primarily focused on cross-sectional data. The aims of this study were to examine the responsiveness of EQ-5D-5L in patients with stroke and to compare it with responsiveness of EQ-5D-3L and visual analogue scale (EQ VAS). Methods: We performed an observational longitudinal cohort study of patients with stroke. At 1 week and 4 months post-stroke, patients were assessed with modified Rankin Scale (mRS) and Barthel Index (BI) and were administered the EQ-5D-5L and EQ-5D-3L, including the EQ VAS. The EQ-5D-5L index scores were derived using the crosswalk methodology developed by the EuroQol Group. We classified patients according to two external criteria, based on mRS or BI, into 3 categories: ‘improvement,’ ‘stable’ or ‘deterioration’. We assessed the responsiveness of each measure in each patient subgroup using: effect size (ES), standardized response mean (SRM), F-statistic, relative efficiency and area under the receiver operating characteristic curve. Results: A total of 112 patients (52 % females; mean age 70.6 years; 93 % ischemic stroke) completed all the instruments at both occasions. In subjects with clinical improvement, EQ-5D-5L was consistently responsive, showing moderate ES (0.51–0.71) and moderate to large SRM (0.69–0.86). In general, EQ-5D-3L index appeared to be more responsive (ES 0.63–0.82; SRM 0.77–1.06) and EQ VAS less responsive (ES 0.51–0.65; SRM 0.59–0.69) than EQ-5D-5L index. Conclusions: The EQ-5D-5L index, based on the crosswalk value set, seems to be appropriately responsive in patients with stroke, 4 months after disease onset. As far as EQ-5D-5L index is scored according to crosswalk approach, the EQ-5D-3L index appears to be more responsive in stroke population
Tilings, tiling spaces and topology
To understand an aperiodic tiling (or a quasicrystal modeled on an aperiodic
tiling), we construct a space of similar tilings, on which the group of
translations acts naturally. This space is then an (abstract) dynamical system.
Dynamical properties of the space (such as mixing, or the spectrum of the
translation operator) are closely related to bulk properties of the individual
tilings (such as the diffraction pattern). The topology of the space of
tilings, particularly the Cech cohomology, gives information on how the
original tiling can be deformed. Tiling spaces can be constructed as inverse
limits of branched manifolds.Comment: 8 pages, including 2 figures, talk given at ICQ
Cytoplasmic PML promotes TGF-β-associated epithelial–mesenchymal transition and invasion in prostate cancer
Epithelial–mesenchymal transition (EMT) is a key event that is involved in the invasion and dissemination of cancer cells. Although typically considered as having tumour-suppressive properties, transforming growth factor (TGF)-β signalling is altered during cancer and has been associated with the invasion of cancer cells and metastasis. In this study, we report a previously unknown role for the cytoplasmic promyelocytic leukaemia (cPML) tumour suppressor in TGF-β signalling-induced regulation of prostate cancer-associated EMT and invasion. We demonstrate that cPML promotes a mesenchymal phenotype and increases the invasiveness of prostate cancer cells. This event is associated with activation of TGF-β canonical signalling pathway through the induction of Sma and Mad related family 2 and 3 (SMAD2 and SMAD3) phosphorylation. Furthermore, the cytoplasmic localization of promyelocytic leukaemia (PML) is mediated by its nuclear export in a chromosomal maintenance 1 (CRM1)-dependent manner. This was clinically tested in prostate cancer tissue and shown that cytoplasmic PML and CRM1 co-expression correlates with reduced disease-specific survival. In summary, we provide evidence of dysfunctional TGF-β signalling occurring at an early stage in prostate cancer. We show that this disease pathway is mediated by cPML and CRM1 and results in a more aggressive cancer cell phenotype. We propose that the targeting of this pathway could be therapeutically exploited for clinical benefit
Spin waves in alloys at finite temperatures: application for FeCo magnonic crystal
We study theoretically the influence of the temperature and disorder on the
spin wave spectrum of the magnonic crystal FeCo. Our formalism is
based on the analysis of a Heisenberg Hamiltonian by means of the wave vector
and frequency dependent transverse magnetic susceptibility. The exchange
integrals entering the model are obtained from the \emph{ab initio} magnetic
force theorem. The coherent potential approximation is employed to treat the
disorder and random phase approximation in order to account for the softening
of the magnon spectrum at finite temperatures. The alloy turns out to exhibit
many advantageous properties for spintronic applications. Apart from high Curie
temperature, its magnonic bandgap remains stable at elevated temperatures and
is largely unaffected by the disorder. We pay particular attention to the
attenuation of magnons introduced by the alloying. The damping turns out to be
a non-monotonic function of the impurity concentration due to the non-trivial
evolution of the value of exchange integrals with the Co concentration. The
disorder induced damping of magnons is estimated to be much smaller than their
Landau damping.Comment: submitted to PR
Correlations, disorder, and multi-magnon processes in terahertz spin dynamics of magnetic nanostructures: A first-principles investigation
Understanding the profound impact of correlation effects and crystal
imperfections is essential for an accurate description of solids. Here we study
the role of correlation, disorder, and multi-magnon processes in THz magnons.
Our findings reveal that a significant part of the electron self-energy, which
goes beyond the adiabatic local spin density approximation, arises from the
interaction between electrons and a virtual magnon gas. This interaction leads
to a substantial modification of the exchange splitting and a renormalization
of magnon energies, in agreement with the experimental data. We establish a
quantitative hierarchy of magnon relaxation processes based on first
principles
An extinction rule for a class of 1D quasicrystals
We study decorated one-dimensional quasicrystal obtained by a non-standard
projection of a part of two-dimensional lattice. We focus on the impact of
varying relative positions of decorated sites. First, we give general
expression for the structure factor. Subsequently we analyze an example of
extinction rule.Comment: 5 pages, 2 figures, LaTex2e, to appear in ICQ9 Proceeding
(Philosophical Magazine
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